Fuel feeding apparatus



Feb. 13, 1945. c. SCHOLL FUEL FEEDING APPARATUS Filed Aug. 28, 1940Patented Feb.'13, 1945 I FUEL FEEDING APPARATUS Clark Scholl,Springfield, Ohio. assignor to The Steel Products Engineering Company,Springfield, Ohio, a corporation of Ohio Application August 28,1940,Serial No. 354,599

, 4 Claims.

This invention relates to combustion apparatus and more particularly tofuel feeding or stoker mechanism.

It is the principal object of the invention to provide mechanism forfeeding solid fuel from a bin in a smooth and regulated manner andwithout excessive grinding or comminuting action upon the fuel itself sothat the mechanism operates efliciently with a small expenditure ofpower.

It is a further object to provide a stoker mechanism for feedingsolidfuel from a bin to a retort which provides for regulating the feedingprogressively from one end of the bin toward-the other, the fuel beingdelivered through and under the body of fuelin the bin which is sosupported and progressively throughout the extent thereof for delivery.

It is a still further object to provide such a mechanismhaving aconveyor tube guiding and supporting a feed worm of the stoker with thetube open along its top for the continuous entry of fuel thereinto andwith its side walls so arranged as to provide support for the body ofvide for storing a quantity of the fuel in a bin from which .it is fedby conveyor or stoker mechanism as required. Where such stoker operatesin a bin of substantial length, or one having a considerable depth ofthe body of fuel overlying the worm, the power required may be quitesubstantial, particularly where the operation of the conveyor results inunnecessary churning or grinding of the fuel, necessitating the use of alarge driving motor and correspondingly heavy drive and operating parts,with consequent increase in both initial and operating costs.

It has been found in accordance with. the present invention that asuperior feeding action may be secured substantially without crushing orcomminuting of the fuel and with a smooth and regu-. lated feedingaction such as to supply a substantially uniform quantity of fuel into aclosed conveyor tube, for example, to be transported therethrough to theretort itself. This regulated supply ,is important where the fuel is tobe conveyed through a closed tube, since uneven feeding tends to causethe supplying ofexcessive quantities of fuel to the closed tube, beyondits capacity to receive the same, resulting in choking thereof withconsequent grinding and attrition of the fuel and corresponding loss ofefliciency.

The .present invention further provides for the discharge of the fuelfrom the inner or remote end of the bin progressively toward the outerend thereof, the feed advancing progressively toward the outer ordelivery end as the supply is exhausted, the fuel in the conveyor beingtransported beneath the main body of fuel in the bin.

Fig. 1 is a broken side elevational view showing a complete installationof a stoker, includ ng of the stoker Fig. 4 is a vertical sectional viewthrough the conveyor tube on the line 4--4 of Fig. 2; and

Fig. 5 is a sectional view through a modified,

form of conveyor tube structure.

In the supplying of solid fuel to a retort in which it is to be burned,it is convenient to pro- Notwithstanding the fact that the conveyor isadapted for receiving fuel along its entire length, the arrangementprovides for an initial and continuing withdrawal of the-fuel at theremote end avoids the tendency to segregate the coarse from the fineswhich normally occurs with a tapered I worm because of the shallowflights having insufficient width to move the larger particles offuelreadily and consequently exerting a selective transporting action withrespect to the fines. lteferring to the drawing which discloses apreoutward bulging thereof.

ferred embodiment of the invention, and referring first to a typicalretort and drive mechanism with which the stoker may be utilized, theretort is The feed worm continues through the closed supply tube whichmay be made in one or more sections joined together by a coupling member2|, as required to cover the necessary distance from the bin to thelocation for the retort. A pair of such coupling members is preferablyprovided and spaced apart a distance corresponding to the length of thesections of the worm so that the worm may be removed therethrou'ghsection by section. A shear plate 22 is provided adjacent the inlet tothe closed tube 20 for the purpose of securing access thereto in orderto clear out foreign objects such as tramp iron, stones, and the like.It will be understood that other forms of retort and drive mechanism maybe utilized, that described above beingshown merely for purposes ofillustration.

The bin is' indicated generally at, the floor of the bin being shown at25 on which rests the body of fuel 26. The stoker conduit extends alongthe length of the bin to the inner end thereof beneath or in the lowerportion of the body of fuel and comprises a cylindrical tube 21 havingan opening 28 along its upper side. The opening 28 is of less width thanthe diameter of the tube and is symmetrically located so that thevertical projection of the walls of the tube along each side of theslot. form shoulder portions 29 in position to provide support for thebody of fuel within the bin, so that the entire weight thereof does notpress downwardly into the tube and yet providing for continuous feedingof the fuel into'the tube throughout its length.

The tube is supported at its inner end by means of a plate 30 having acircular cut-out portion ment therebetween. The flights on each sectionadapted to he slipped over the end of the tube and attached thereto asby welding, and having an angle member 3| fastened at its bottom portionserving as a foot for resting upon the floor 25 of the bin. Additionalsimilar brackets 32 having angle members 33 welded thereto may beprovided as desired giving intermediate support to the conveyor tube thetube being supported relatively close to the floor to provide for'morecompletely discharging the bin contents. In addition the tube isreinforced by means of plates 35 which have asimilar cut-out portionadapted to be received over the outside of the conveyor:

tube and which are trimmed off at the top at the level of the upper wallof the tube, as shown for example in Fig. 4. These brackets are spacedsuitably along the length of the conveyor tube and welded in place, sothat they provide rein-.

forcement for the walls of the tube and prevent The forward end of thetube 40-is suitably attached to an end plate 4| by means of welding,

the end platebeing adapted .to stand at the outer itate the removal offoreign objects which may get caught between the worm and the shearplate, the side wall of the tube immediately adjacent the plate 4| ispreferably beveled down to the center line at an angle of about 30 asshown at 42.

Within tube 21 is the feed worm 45 having continuous flights 46 formedthereon. Preferably the worm is made in a plurality of sections whichare joined by a coupling 41 formed with a tongue 48 in one sectionfitting within a groove 49 in the other section permitting relativeangular moveextend to the ends thereof, and in the assembled positionmatch up with each other to provide a continuous and unbroken feedingsurface free of obstructions or'pockets such as would interfere with thesmooth uniform feeding operation.

Such cooperating flight ends are adapted to bear against each other, sothat a substantial part of the torque is transmitted from the drivingsection to the driven section in this manner, relieving the load uponparts 48 and 49. The coupling member may be disconnected, in order toprovide for the removal of the sections ofthe worm axially, provisionusually being made for such removal in the space between the bin and theretort, the length of .the sections being suitably selected so that theymay be pulled axially into this zone and then withdrawn upon the removalof the coupling members 2| as above described. Where there isinsuflicient space for this, the drive unit may be removed, and the wormwithdrawn from the drive end,section by section.

As will be clear from the drawing, the'conveyor worm is entirelysupported and guided by the walls of tube 21, and no additional bearingseither at the inner or theouter end of the bin being provided. Thisassures that the flights of the worm will run freely, and usually incontact with the lower wall of the bin so as to provide for thecontinuous discharge of particles of all ranges of size. It alsoprovides for limited lifting movements of the worm within the tube whichmay occur as the worm accommodates itself to the movement of the fuel inoperation. As clearly shown in Fig. 2, the top edge of the flights 48extends slightly above the wall portions 29 of the tube, and in positionto readily engage and pick up the body of fuel for transport through theconveyor.

It has been found that the width of the slot should bear a properrelation to the size of the worm, in order to provide for proper freedomof access of the fuel to the worm and at the same time to assure thedesired support for the fuel upon the shoulders of the tube. Further theopening in the slot should not be so wide that it would permit the wormto rise and wedge itself in the slot. It is ordinarily found that thewidth of the slot should be approximately 75% to of the diameter of theworm, the remainder of the projected worm diameter forming the shoulders29 and serving to support the fuel thereupon.

.In the operation of the device, with the bin containing a body of solidfuel over the conveyor tube, rotation of the worm tends to cause theflights to pick up fuel, and after being loaded with the fuel, nofurtherfeeding action occurs except at the innermost end where the worm begins.At this zone, fuel is progressively fed into the worm, and carried alongby the worm, beneath the main body ofthe fuel.- This main body is thussupported above the worm, the shoulders 29 of the tube giving supportthereto so that the entire weight thereof does not press downwardly onthe worm. N

Any tendency for the fuel to pack in the tube is overcome by the freeand unconfined movement of the fuel, with resultant lifting of the fueloutwardly and upwardly through the open slot in case of any tendency tocrowd or to build up pressure within the tube. As the feeding actioncontinues, and as the body of fuel is progressively ex-.

hausted, the fuel rolls downwardlyalong the outer edge of the pile andinto the portion of the worm which lies beneath the edgethereof,'to-fill the.

of the worm which is possible in the tube it is l found that thetendency of the worm to tunnel,

and of the fuel to bridge over the conveyor tube a and thus terminateits feeding action is substantially eliminated, no tendency to stopfeeding by reason of the fuel bridging over the slot having beenobserved even in the case of fuel of small particle size and in a dampcondition. The worm, being freely supported in the tube, is allowedcertain movement which may be imparted to the conveyor tube as well, andthis movement sufficiently agitates the body of fuel to cause it to flowdownwardly into the slot in the desired progres sive manner from theinner to the outer end of the bin.

This arrangement provides for a regulated and substantially uniformfeeding action, and the worm does not tend to pack, to grind the body offuel therein, or to deliver an excessive quantity of fuel from the bin.Hence the closed tube 20 may be of the same or larger diameter, thantube 21, and assurance is provided that no excessive loading or packingof the fuel into the closed tube will occur. Thus a relatively smallsized drive motor may be utilized, and the conveyor operated with theexpenditure of only a very small amount of power, resulting ineconomical and highly eflicient supply of fuel in substantially thecondition in which it exists in the bin, into the retort for ,theinvention, it is to be understood that the invention is'not limited tothese precise forms of apparatus and method, and that changes may bemade therein without departing from the scope of the invention whichisdefined in the appended claims: I

I What i claimed is: a

1. A stoker of the character described fordelivering solid fuel from abin containing a quantitythereof to a closed conveyor tube for delivcryto a retort comprising a cylindrical tube extending through the wall ,ofsaid bin and into the remote end thereof, means for supporting said tubeclose to the bottom of said bin, said tube having a continuous slotopening directly upwardly along its entire length within the bin forminga central longitudinal continuous opening for the introduction of fuelthereinto and leaving shoulders at the sides of the tube for supportingthe weight of the fuel thereon, a plurality of spaced plates fastened tothe walls of said tube adjacent the sides of said slot to reinforce thesame and prevent the spreading thereof, a conveyor worm of uniformdiameter greater than the width of said slot extending through said tubeand entirely supported and guided by contact with the walls thereof andcapable of limited movement relative thereto, said worm being adapted tofill itself with fuel at the inner end of the bin and to deliver saidfuel along the tube beneath the body of fuel supported on the shouldersof said tube, a closed delivery tube in line with said slotted tube andadapted to receive the fuel therefrom, and a continuation of saidconveyor worm extending into said closed tube to continue the regulatedfeeding of said fuel thereinto.

2. A stoker of the character described for delivering solid fuel in arelatively loose and unpacked condition from a bin containing a quantitythereof to a closed conveyor tube for introduction into a retort with aminimum expenditure of power and in the absence of grinding and crushingof the fuel comprising a screw conveyor having continuous flightsthereon and of substantially uniform diameter, a cylindrical tubesupported adjacent the lower part of the bin and extending from an innerportion thereof throughout the feeding zone and forwardly to the Wall ofthe bin through which the fuel is discharged, said tube providing thesole support for rotatably supporting said screw conveyor throughcontact with the inner wall surface thereof, the top portion of saidtube being cut away to form a continuously open slot the cross dimensionof which is approximately 75% of the projected diameter of the tube,said slot being of such width that said screw conveyor is rotatablyretained within said tube and leaving shoulders at either side of theslot providing continuous support along the sides of the tube for themain body of fuel within the bin and relieving the flights andthe fuelmoving through said tube from the weight thereof, said slot providing anentrance open along the length of the tube for passage of the fuel intothe flights of the screw conveyor in that l I portion thereof not filledwith fuel, the fuel passing into and filling the conveyor at the innerend' of the body of fuel and being conveyed forwardly with the flightsmaintained substantially filled with fuel beneath the main body of fuelwith the point of entrance of the fuel into the tube progressivelymoving forward with the advance of the inner boundary of the body offuel, and means confined to the space outwardly of the cylindricalsurface of said tube for reinforcing the walls ofthe tube to provide formaintain ing the original size and shape thereof and avoidingirregularities in the flow of fuel theretherein directly in contact withsaid body of fuel,

said tube being of substantially cylindrical shape and having acontinuous open slot extending along its upper portion oversubstantially the en width of said slot and with a substantial num- Yber of such flights being exposed through said open slot, thetopmostportion of said flights extending into the area of said slot above saidshoulders tofeed fuel forwardly from said body of fuel, said wormproviding for picking up fuel and filling its flights at the innermostportion of the tube above which there is a body of fuel andprogressively at all points forwardly thereof as the body of fuel isexhausted to move the same feeding solid fuel from a, bin comprising agenerally cylindrical tube in the lower portion the bin beneath and indirect contact with body of fuel therein. said tube having an open sloton its top portion extending continuously over its lengthwithin the binproviding for entrance of fuel thereinto at any point with the fuelpassing into said tube to flll the same progressively from the remoteend of the bin, said slotbeing of less width than the tube'diameterforming continuous fuel supporting shoulders in the walls of the tubeabove the level of the tube axis at either side thereof, and a wormconveyor having flights thereon the uppermost portions of which projectabove the level of said shoulders and within the uppermost projection ofthe cylinforwardly beneath the remaining body of fuel I thereoverwithout additional filling and with substantially minimum grinding andpacking of the fuel. I

4, Apparatus of the character described for drical surface of the tube,the topmost portion of a substantial number of said flights beingexposed along said open slot and above said shoulders, said exposedflights remaining fllled with fuel as initially received therein andconveying said fuel beneath the remaining body of fuel withoutsubstantial addition to or replacement thereof.

CLARK SCHOLL.

